1. Field of the Invention
Embodiments of the invention relate to the field of video broadcast, and more specifically, to private user data in broadcast video.
2. Description of Related Art
Motion Picture Experts Group (MPEG)-2 video standard provides format for broadcast quality video with resolutions up to 1920×1080 and beyond. The MPEG-2 video standard specifies video bitstream syntax as described in the specification document published by the International Organization for Standardization (ISO)/the International Electro-technical Commission (IEC), Document No. 13818-2, 2000 The video bitstream syntax includes format for video sequence, sequence header, and extension and user data. The user data concept is intended as a general purpose container for types of data not to be described in an ISO standard, such as data provided by private entities. However, the MPEG-2 video standard does not address how a receiving device may identify the owner of a particular block of private user data it may encounter. The originator of the private data block establishes its format and content. Therefore, reliable determination of the identity of the originator is essential for the receiver to successfully access and use of private data.
The MPEG-2 video standard is used in the Digital Television (TV) standards supported by the Advanced Television Systems Committee, Inc. (ATSC), among others. ATSC is an organization that develops standards for digital television. The ATSC DTV standard describes the picture user data syntax that includes a four-byte field used to identify the structure and contents of the data to follow. The ATSC user data identifier is specifically defined by ATSC as consisting only of pre-defined (standardized) values identifying standardized data structures. The ATSC standard specifically states that receiving devices are expected to discard any unrecognized video user data encountered in the video bit stream.